These days, the manufacturing of a semiconductor device using a mounting method of what is called the face-down system is performed. In the face-down system, a semiconductor chip (hereinafter, occasionally simply referred to as a “chip”) having electrodes such as bumps on a circuit surface is used, and the electrodes are joined to a substrate. Hence, the surface on the opposite side to the circuit surface of the chip (chip back surface) is exposed.
In order to protect the exposed chip back surface, a protective film formed of organic material is disposed on the chip back surface in some cases, and the protective film-equipped chip having the chip back surface protected with the protective film may be directly incorporated into a semiconductor device in some cases.
With the densification of a semiconductor device installed with a semiconductor chip and the speeding-up of the manufacturing process of the semiconductor device in recent years, the heat generation from the semiconductor device is becoming a problem. There are cases where the heat generation of the semiconductor device causes a deformation, trouble, or breakage of the semiconductor device or causes a reduction in computing speed or a malfunction of the semiconductor device, and this leads to a reduction in the reliability of the semiconductor device. Thus, efficient heat dissipation properties are required for semiconductor chips incorporated into high performance semiconductor devices. Accordingly, the heat dissipation properties are required for the protective film of the protective film-equipped chip.
Since characters are printed on the surface of the protective film by laser marking in some cases, the protective film to be formed is required to have visibility of the laser printed portion.
In the case of a protective film-equipped semiconductor chip being incorporated into a semiconductor device, lifting-off, peeling-off, and cracks occur in the joint portion of the semiconductor chip with the protective film due to temperature change by the repetition of heat generation and cooling, resulting in a problem of reduction in the reliability of the protective film-equipped chip.
In order to form a protective film meeting the requirement, various materials for protective film formation have been proposed.
For example, Patent Document 1 discloses a film for the back surface of a flip chip type semiconductor, which contains a resin and a specific amount of heat conductive filler having an average particle size and a maximum particle size of specific values or less, respectively, in order to provide a film for the back surface of a semiconductor excellent in heat dissipation properties, with the visibility of the characters on the surface and the adhesion with a semiconductor wafer or the like being maintained.